Newshound Posted March 21, 2012 Author Report Share Posted March 21, 2012 My 912 ULS is 4.3 years old. It sat for 3 years before being put into service. Rotax long term storage procedures were followed. It has 188 hours since going into service and has performed without any problems until the last attempted flight. The start was normal including a run up at 4000 RPM with mag drops of 100 RPM each side. Seconds after going to full throttle for take off the engine started running very roughly with a large RPM drop and loss of power to the point that it stalled. However the stall may have been caused by my panicked pull back on the throttle to abort the take off. I didn't roll more than a couple hundred feet on asphalt. I have a facet fuel pump backing up the mechanical fuel pump and it is always on for take off and landing. After checking everything that I could think of I did a restart on the other gas tank. This time I was lined up for take off but not planning on going anywhere. I got exactly the same performance. Everything is fine until going over 5000 RPM. The gas is fresh 94 octane mogas (Canada). I tried with the electric fuel pump on and off. After a dozen tries and cowl removal and trying I gave up for the day.The next day I replaced the spark plugs and again everything was fine until going over 5000 RPM. If I throttle back it will sometimes clear itself at a lower RPM without stalling but this is not immediate taking perhaps 30 seconds before it runs smoothly.I have attached a picture of two plugs, one removed at 100 hours and the second removed since the problem developed at 188 hours. The bottom left plug with the beige deposits is the 100 hour plug while the upper right plug with the black deposits is the plug removed after a dozen tries as mentioned above. All 16 plugs are showing the same characteristics, eight beige (100 hours) and eight black (188 hours).The black deposit makes me think (in my infinite ignorance) that the engine is flooding. I checked the chokes several times and they are indeed going to the off position.And a special thanks to my engine for quitting at 0 feet instead of 300 feet. My landing options are trees or water.More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 21, 2012 Author Report Share Posted March 21, 2012 alguien me puede ayudar en encontrar las tablas de especificaciones para los chicleres para regular mi carburador 64 del 912 ULS, yo opero en una altitud de 1500 pies y a una temperatura de 30 grados centigrados graciasMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 23, 2012 Author Report Share Posted March 23, 2012 Saw an unusual situation with a 912uls installation today. Due to constraints in the engine compartment, the muffler had to be located with about 15" of space between the bottom of the engine and the top of the muffler. The owner has had no problems with the installation, but this is the question that came up. When engine torque tries to twist the engine, particularly at shutdown, the farther the muffler is from the engine, the more it tries to resist this movement. At what distance does this become a structural problem? Does Rotax have any recommendations as to the maximum allowable distance below the engine the muffler should be located?Bill.More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 23, 2012 Author Report Share Posted March 23, 2012 Sometimes (about 50%) there is no light from charge control lamp after engine shut down. If I crank the engine just 1/2 rew after shut down the control lamp lights again.The control lamp always lights with key switch on before starting the engine. = okThe control lamp newer lights when the engine runs. (except for some glowing during low rpm)= okI have no charging problem. The alternator seems to work and the battery is in good conditon. = okI have replaced the control lamp and the key switch but the problem remains.Does anyone have an idea what's wrong?Regulator?(Sorry for the bad English, I'm from Sweden..)More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 23, 2012 Author Report Share Posted March 23, 2012 Fitted as per 'book' one EGT probe in each front exhaust, 100 mm from flange.Several trial runs and then left carb needle dropped one groove to #2 from the topThe following results obtained but should they not all read 780+-20 deg. Centigrade ?So can anyone say if these readings are correct and 'normal' please ?5,200 rpm WOT climb Left front EGT 780 C, Right 800 degrees C.5,000 rpm ..S & L .................700...........7704,800.......S & L..................675...........7104,600.......S & L..................690...........6904,500.......S & L..................675...........6754,200 S & L..................650...........660.mike hallam GBMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 24, 2012 Author Report Share Posted March 24, 2012 In looking at the pressure cap on the coolant header tank it looked like it had a bad seal so I orddered a new pressure cap. I will say I was shocked at the price ($75.00 plus shipping). Hopefully Rotax will cover it under warranty since it definately was bad. Anyway, serviced the engine with coolant and installed the new cap and flew it on a short trip of 2 1/2 hours (round trip)for the infamous $100 dollar hamburger. Checked the coolant systemm after returning and everything was perfect with no coolant loss. So the moral of my story is if you are loosing coolant and can't find a leak, you might want to check out your header tank pressure cap.More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 25, 2012 Author Report Share Posted March 25, 2012 Hello Guys,I have a problem with my Rotax 912 with only 86 hours of use. During the engine running magneto test. One of my magnetos is losing 800 RPM. We have check everything and when I change one ignition module to the other side the problem change to that side. Since I want to test if my ign modules are OK, I have a buddy that will help me and let me use his modules but his engine is a 914 Turbo.His modules and mine have the six pin connectors but can I still use them for the test???THX,IsaacMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 26, 2012 Author Report Share Posted March 26, 2012 I am building an Aerospool Dynamic using the 912ULS. Fuel system assembly instructions are limited. I have a question about the fuel hose size supplying the fuel pump. The factory supply hose is 5/16" ID with an AN-6 female swivel for the firewall. I don't understand why this hose is 5/16" when the system is 1/4" prior to the firewall. The airplane uses 1/4" fuel hose from each tank to an Andair fuel selector which uses 1/8"NPT inlet fittings and then continues to a Facet fuel pump, also with 1/8" NPT fittings. Each tank is selectable. So, Why does the pump inlet hose jump to 5/16"? Fuel flow is only as good as the most restrictive flow. Will there be an issue if the fuel tubing is left at 1/4" to the firewall and then stays 1/4" to the pump? I would really appreciate the reasoning behind the jump up in fuel hose size.Thanks.BradMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 26, 2012 Author Report Share Posted March 26, 2012 Tengo problemas en conseguir una temperatura adecuada de solo un lector del EGT de mi motor Rotax 912 ULSEste motor volo durante 7 años en una ciudad de Bolivia que esta situada a 8500 Pies de altitud en este momento este motor se encuentra en Santa cruz Bolivia a un nivel de 1370 Pies cuando regulamos los carburadores segun el procedimiento de fabrica encontramos que la posicion del nivel de las agujas estaba en la posicion 3 , esto significa que este motor estaba trabajando con una mescla bastante rica para el nivel donde volaba Cambiamos la poscision de las agujas para la posicion de fabrica (2) pero no conseguimos ni hacer un vuelo de prueva pues los niveles de temperatura de los EGT sobrepasaron los 880 en tres cilindros Bolvimos a cambiar el nivel de la mezcla a la posicion 4 y fua entonses que pudimos mantener todos los EGT en parametros normales con esepcion del piston numero 1 que continua con una temperatura de 880 a las 5500 RPM Sacamos las bujias y las mismas denotaron que estoy operando el motor con una mezcla demasiado enriquecida pues el color de las mismas es negrode igual manera en la prueva de magnetos los mismos bajan por debajo de lo indicado en el manual 500 RPM y el motor bibra muchisimo en la prueva de magnetos inclusive con bujias nuevas .Rogaria a los amigos si pudieran ayudarme de alguna manera a resolver este problema .Saludos Jimmy Vargas Santa CruzMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 26, 2012 Author Report Share Posted March 26, 2012 Tengo problemas en conseguir una temperatura adecuada de solo un lector del EGT de mi motor Rotax 912 ULSEste motor volo durante 7 años en una ciudad de Bolivia que esta situada a 8500 Pies de altitud en este momento este motor se encuentra en Santa cruz Bolivia a un nivel de 1370 Pies cuando regulamos los carburadores segun el procedimiento de fabrica encontramos que la posicion del nivel de las agujas estaba en la posicion 3 , esto significa que este motor estaba trabajando con una mescla bastante rica para el nivel donde volaba Cambiamos la poscision de las agujas para la posicion de fabrica (2) pero no conseguimos ni hacer un vuelo de prueva pues los niveles de temperatura de los EGT sobrepasaron los 880 en tres cilindros Bolvimos a cambiar el nivel de la mezcla a la posicion 4 y fua entonses que pudimos mantener todos los EGT en parametros normales con esepcion del piston numero 1 que continua con una temperatura de 880 a las 5500 RPM Sacamos las bujias y las mismas denotaron que estoy operando el motor con una mezcla demasiado enriquecida pues el color de las mismas es negrode igual manera en la prueva de magnetos los mismos bajan por debajo de lo indicado en el manual 500 RPM y el motor bibra muchisimo en la prueva de magnetos inclusive con bujias nuevas .Rogaria a los amigos si pudieran ayudarme de alguna manera a resolver este problema .Saludos Jimmy Vargas Santa Cruz BoliviaMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 26, 2012 Author Report Share Posted March 26, 2012 I have Problems with the adjustment of the temperatures of the EGT of my motor Rotax 912 ULSThis motor operated in the city from Cochabamba to an altitude of 8500 Feet At this time that motor is operating in the city of Santa cross that is to an altitude of 1370 Feet In the city of Cochabamba they operated him with the needles in the position 3 and according to their operator they never had reading of bigger at 750° in the EGTNow in Santa Cruz we have made all the adjustments from the carburetor to the suitable ones for it manufactures, but the temperatures of all the EGT surpass the normal parameters (up of 880) All the other parameters CHT is inside the normality We placed the adjustment of the needles in the position 4 again and the EGT normalized 2,4 the 3 this inside the normality but slightly bigger at 2 4 but the 1 you ascends at 880 to low alone 550 RPM at 834 to 4900 RPMWe take out the spark plugs and the same ones denoted that we are with an excessive rich mixture because the color of the same ones is dark (black)In the same way in the test of magnetos the RPM falls more than the normal thing 500RPM and there is a strong vibration.We would like to see the possibility that if some friend can help us with this problem Greetings Jimmy Vargas Sacred Cruz BoliviaMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 27, 2012 Author Report Share Posted March 27, 2012 how many time one rotax engine is overhauled? there is any limitation for TBOMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 27, 2012 Author Report Share Posted March 27, 2012 What should I do? The gas (it's avgas) wasn't changed either; worried my carburetors may be gummed up. I purchased the plane (A Chinook Plus 2) approximately two years ago (I'm a new UL pilot with low hours of experience), and unfortunately due to circumstances beyond my control, haven't been able to fly it or do any run-ups for the last 1.5 years.I live in a remote area (Kirkland Lake, ON, Canada) and would like to do as much of the maintenance work on my own as possible.I think it's time for air filter replacement, oil & oil filter change, spark plug change, fuel filter change, magnetic plug inspection, etc. What parts should I order and where can I get them from?Worried that I may do damage to the engine if I start it with the oil having possibly drained away from critical components after 1.5 years of sitting.Any advice would be greatly appreciated!More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 29, 2012 Author Report Share Posted March 29, 2012 Our plugs on our 600 hour Rotax 912UL are about due for changing.A bit of a dilemma:Took a 16-hour LSA repairman/inspector course from an very experienced Rotax A&P mechanic last year.He said that Rotax recommends coating threads on plug with a heat transfer compound... thermal paste.It's usually either a grease with aluminum powder or more comonly silver powder.Was specific that "if that's what Rotax says, that's what I'd use. Nothing else.Idea is that by perfect thermal contact at the threads the plug will run at expected design/intended temperatures.(I'm familiar with that sort of compound... In the computer business, which I'm in, we use it on top of a CPU chip {which produce a lot of heat] to make good thermal contact with the heat-sink that cools/disspates the heat.)Unlike anti-seize you won't find it at NAPA, but since I'm in the computer trade not hard to get (just shop for heat-sink-thermal-compound.Anyway, the previous owner who had this rotax for the first 400 hours of its live used conventional sparkplug thread anti-seize compound, and the plugs look darn near perfect even at 200+ hours.So I'm torn between "do what Rotax says" and "if it worked fine before keep doing what works."Any info or opinions on this one?AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 29, 2012 Author Report Share Posted March 29, 2012 Warmed up engine took off climbed to 500 ft pulled power back to 5000 rpm cruised for 5mins into the curuit pulled power to 3000 rpm went to increase power soon as l push throttle forward engine stop.No miss no sign of anything wrong.Landed safely engine restarted fine cant find any thing wrong any suggestions.Cheers Geoff..More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 31, 2012 Author Report Share Posted March 31, 2012 Warmed up engine took off climbed to 500 ft pulled power back to 5000 rpm cruised for 5mins into the curuit pulled power to 3000 rpm went to increase power soon as l push throttle forward engine stop.No miss no sign of anything wrong.Landed safely engine restarted fine cant find any thing wrong any suggestions.Cheers Geoff..More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted March 31, 2012 Author Report Share Posted March 31, 2012 Older 912UL (1997) with no air box and 138 hours total time on a Zenith CH701.I knew the aircraft had carb problems when I purchased it so I overhauled both Bing 64 CV carbs. Needle jet is changed to 2.74 (it was running lean with a 2.76 even at position #4) and needle position at position #1. They appear to be functioning correctly (I synced mechanically and pneumatically) and I idle smoothly at 1800 RPM and it runs smoothly through the RPM range up to 5500. Idle air mixture screw is set at 1 1/4 turns (1 1/2 was too rich, I fly out of a 2100’ elevation strip). There is no dribbling from the carb overflow vent and the float levels are set level. I’ve got the prop (warp drive 68â€) set for 5500 on take off.The #2 EGT (cyl. 3) runs high. It has run high since I purchased the aircraft. The probes are 68mm from the port (not 100 as the book says) and I checked to make sure the probes are grounded well (they are). I still get more than 100 degree split between right and left. The plugs look good (medium brown) with the #3 cylinder possibly a little whiter.Usually the EGT is below the red line on takeoff and climb, but shortly after level off I can see temps over 1650 on the #2.A differential compression check shows the weakest cylinder at 77 over 80 with the leakage around the rings (it was warmed up).Any input on the EGT would be appreciated. Oh, and I did do an intake leak check by spraying starter fluid around the intake while it was running. No apparent leak.Next issue. The last two times I have flow the aircraft the engine wouldn’t shut down completely. I could go to idle, shut one switch off a few seconds and then turn the key off (yes, it is a key switch) and it would kick over for 45 sec, to a minute. Once I even had to shut the fuel off to shut it down.I check the ground at the switch, cleaned the grounding wires to the intake manifold and gapped the plugs at .26. The second time is when I lowered the idle to 1800 from 2000 and it still does it. It does have a mag drop of approx. 400 on each side and when I do a mag switch grounding check taxiing out it appears to ground OK. Its the shutdown when it is hot.Being an older engine it has both ignition modules on top of the engine (yes it has the ground wire service bulletin complied with and it is grounding well).Sorry this post is so long. I’ve been dinking with this for 4 months now. I’ve picked up a lot of good information from this forum but I’m about at the end of my know how here. Any suggestion would be appreciated.More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 1, 2012 Author Report Share Posted April 1, 2012 Can the forum members provide comments on their experience on the Inflight adjustable Carbs, VS the Presure compensating Carbs.I know that Green Sky Adventures makes a In flight one.I have also heard of fuel injection for the 503I am wanting to fly between 1600 to 8000 feet with a 503 dual carb Rotax, often at the higher power settings.The degree days go from cold to over 95 in the summer months.More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 2, 2012 Author Report Share Posted April 2, 2012 Hello guys,I have a problem with my 912 and I want to send the engine to a Rotax Service Repair Facility in Florida.I know there is lockwood aviation repair in FL but Have any of you have experienced with them?What other Rotax Service Repair Facility in Florida you can recomend me.THX,IsaacMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 2, 2012 Author Report Share Posted April 2, 2012 recently bought a tecnam p92 with low hrs. powered by 912 uls. on t/o tach reads 5100 climbs out very well.lvel cruise is usually around 4000 rpm. is it caused by to much pitch on prop?More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 3, 2012 Author Report Share Posted April 3, 2012 i should have explained better.the reason i was asking about the low rpm was because i read that the 912 should turn faster than mine is. the most i can get out of it is 5100 on takeoff at cruise i pull it back to about 4000 because it seems to perform well enough. am i flying it at to low rpm? the engine runs fine. starts quickly even when cold and runs smoothly thanks for your replyMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 3, 2012 Author Report Share Posted April 3, 2012 Not a pressing urgent issue, but curious:When I tried to go to the Profile tab I get the message: `The profile page has been disabled You do not have permissions to access this page.`Any ideas?AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 3, 2012 Author Report Share Posted April 3, 2012 If a Rotax 912UL is getting excessive RPM drop when the right mag is switched off on runup,which four plugs (and their wiring) need to be investigated?We have had in the past a bit more roughness and a bit more drop when turning off the right mag than when turning off the left mag on runup in the past. All within specifications. But not symetrical. Put in new plugs today. Old plugs had 200 hours on them.(They looked text-book perfect -- really probably din`t NEED to be changed)Install per Rotax specs, small amount of heat-transfer compound on upper threads, used torque wrench to tighten exactly.Starts and runs fine...BUT: After new plugs installed on run-up when turning off right mag we now get an even greater (and out of spec) RPM drop. Like a 500 rpm drop now. Theory-1: Is I wonder if maybe I didn`t get one of the plug leads/caps on really snug (although I double checked)or somehow got something on one plug`s electrode?Or got one plug`s lead/cap loosened off its wire?Theory-2: Is that whatever was going on before I changed the plugs was excerbated during the change. Like maybe I damaged and already defective plug lead during handling while changing the plugs.In any case now need to investigate what plugs/leads are fed by the left mag.Don`t know which those are. Anyone know specifically which plugs/leads are fed by the left mag?All help appreciated as knowing which four to investigate could cut down my trouble-shooting and wire-checking time by half .AlMore... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 3, 2012 Author Report Share Posted April 3, 2012 Can any one tell me if the TBO of 1200 hrs has been extended on the 912 UL engine #4152868I am up to 1000 hrs and it is running fine all cylinders are all 80/80 on the leakdown test. More... Quote Link to comment Share on other sites More sharing options...
Newshound Posted April 3, 2012 Author Report Share Posted April 3, 2012 I have a 912 UL fitted on my Rans S-12 Airaile. I live in the Philippines (tropics). When I start the engine from cold (after burping) with full choke and closed throttle, the engine fires and idles smoothly. Warm up takes 'forever' but engine runs real sweet throughout the whole rev range. So, that's the easy part.After returning from a flight and shutting down, I cannot get the engine to restart. The best I can manage is for the engine to fire and run so roughly that it is shaking engine and airframe apart. If I advance the throttle, the engine will not increase rpm and either stalls or continues to rattle. If I persevere (which I am loath to do because of the damage the vibration must surely be causing) the engine will, after about 45-90 seconds, suddenly spring to life and run smoothly. I have tried choke; no choke, throttle; no throttle - it makes no difference.When the engine has been rattling itself to death, I have run a mag check; this doesn't affect the engine rough running in any manner but neither does the engine stop (ruling out an ignition problem!)I've had the carbs stripped, cleaned and tuned; still no improvement! Battery is good; proved by the engine starting okay from cold!I'm not an engine mechanic but my A&P guy (who has received some Rotax training) is also at a loss. We don't want to spend on replacement carbs or any other parts until we can definitively determine the cause.The problem now has me grounded so I am desperate for help.Thanks in advance to anyone who might have some ideas! More... Quote Link to comment Share on other sites More sharing options...
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